| Petronius Maximus | |
|---|---|
 | |
| Roman emperor in the West | |
| Reign | 17 March – 31 May 455 |
| Predecessor | Valentinian III |
| Successor | Avitus |
| Eastern emperor | Marcian |
| Born | c. 397 |
| Died | 31 May 455 (aged c. 58) Rome |
| Spouse |
|
| Issue | Palladius |
| Father | Possibly Anicius Probinus |
Petronius Maximus (c. 397 – 31 May 455) was Roman emperor of the West for two and a half months in 455. A wealthy senator and a prominent aristocrat, he was instrumental in the murders of the Western Roman magister militum, Aëtius, and the Western Roman emperor, Valentinian III.
After the assassination of the Western Roman magister militum, Aëtius, and the subsequent death of the Western Roman emperor, Valentinian III, Maximus secured the support of the Senate and utilized bribery to gain the favor of palace officials, enabling him to ascend to power. He strengthened his position by forcing Licinia Eudoxia, Valentinian's widow, to marry him and forcing her daughter Eudocia to marry his son, cancelling her betrothal to the son of the Vandal king Genseric. This infuriated both Eudocia and Genseric, who sent a fleet to Rome. Maximus failed to obtain troops from the Visigoths and he fled as the Vandals arrived, became detached from his retinue and bodyguard in the confusion, and was killed by fellow Romans. The Vandals thoroughly sacked Rome in their retaliatory invasion.
The reign of Petronius Maximus marked a significant period of instability and decline for the Western Roman Empire. His brief and controversial rule reflected the political fragmentation and lack of centralized authority that plagued the empire during its final years. The invasion and sacking of Rome by the Vandals underlined the growing vulnerability of the Western Roman Empire, which would ultimately culminate in its collapse in 476.